The present invention relates to the use of a stabilized, particularly a stabilized, crosslinked waxy potato starch to increase the viscosity of a composition, particularly a food product. Starch is the primary form of carbon reserve in plants, constituting 50% or more of the dry weight in many storage organs, i.e., tubers, seeds of cereals. It consists of two major components: amylose, an essentially linear polymer of (1xe2x86x924) xe2x88x9d-D-glucopyranose units; and amylopectin, a branched polymer of shorter chains of (1xe2x86x924) xe2x88x9d-D-glucopyranose units with (1xe2x86x926) xe2x88x9d branches.
Starch in various forms is of great importance in the food and paper industry. Many different starch products are known which originate from, inter alia, maize, tapioca, rice, and potato. In many cases, however, it is necessary to modify the native starches, via chemical, biochemical, and/or physical means, in order to produce the distinct properties necessary to suit particular applications.
Maize starch which is substantially pure amylopectin is also known as waxy maize starch. As used herein, waxy potato starch refers to a potato starch which is high in amylopectin. Waxy-type starches are useful for food applications in that their functionality differs from starches higher in amylose. When starch is heated in an aqueous medium, the granule swells. During this swelling, amylose tends to solubilize and leach out into the surrounding water where it reassociates through hydrogen bonding to initiate gelation, forming a paste that becomes cloudy and opaque as it cools. Over a period of time, the starch network continues to shrink, resulting in a stronger gel which can also result in the release of water. The configuration of amylopectin discourages reassociation so that gelling does not readily occur and the resulting pastes are more flowable and clear.
Several processes have been developed to produce a starch high in either amylose or amylopectin, including physical means of separation, classical plant breeding, and genetically engineered modification of the plants such that primarily one type of starch is produced. For example, WO 92/11376 and CA 2,061,443 disclose genetically engineered modification of potato starch to suppress the formation of amylose, producing a potato with a starch content containing essentially pure amylopectin.
Starch functionality can be chemically modified as well. For example, the swelling and subsequent rupture of starch granules during cooking can be controlled by introduction of difunctional agents capable of reacting with the hydroxyl groups of two different molecules within the granule. This is called cross-linking or inhibition. The synthetic bonds reinforce the natural hydrogen bonding, retarding the rate of granule swell and reducing the sensitivity of the swollen granule to rupture. This results in cooked pastes which are more viscous and heavy bodied and are less likely to breakdown with extended cooking times, increased acid or severe agitation.
Waxy starch pastes show little tendency to gel or retrograde when stored under normal conditions at ambient temperatures. However, when stored under refrigerated or freezing conditions, a waxy paste tends to become cloudy and chunky and will release water similar to pastes made with amylose-containing starches. Stabilization reduces the tendency of waxy starches to lose their hydrating ability and clarity upon storage at low temperatures.
Various starches are known to be useful as thickeners in the food industry. However, it is generally preferable to limit the use of starch for several reasons. Firstly, starch adds flavor to foodstuffs. In many foodstuffs, this starchy or cereal flavor is undesirable and difficult to mask.
Secondly, high levels of starch add cohesiveness to foodstuffs. Such texture is undesirable in many foodstuffs where the consumer prefers a shorter texture, such as one that is creamy and/or smooth.
Thirdly, starch adds opacity to foodstuffs. In many foodstuffs, it is desirable to have more clarity; not only to produce clearer foodstuffs, but also to provide truer colors.
Fourthly, starch adds calories to foodstuffs. Currently, a significant segment of the consumer market is watching their weight. Therefore, lower calorie foodstuffs are often desirable. By adding less starch, which contributes approximately 4 Kcal/g, and replacing the unnecessary starch with lower or no calorie bulking materials, the calorie content of a foodstuff can be decreased.
Fifthly, functional starch may be costly. Many starches which add specific functionality to foodstuffs are expensive due to the modifications which provide the functionality. Using less starch could therefore reduce the cost of producing the foodstuff.
Surprisingly, it has now been discovered that certain stabilized, particularly stabilized and crosslinked, waxy potato starches, have unexpectedly high viscosities such that they can provide the desired viscosity to a composition while using substantially less than would be need if using a conventional starch thickener or viscosifier.
The present invention is directed to an unexpectedly high viscosity modified waxy potato starch obtained by controlling the type and degree of stabilization, particularly the type and degree of stabilization and the level of crosslinking. Such starch is useful as a thickener or viscosifier. By using such starches, the same magnitude of viscosity may be obtained using less starch than if other starches were used, including stabilized or stabilized and crosslinked starches originating from other grains including potato, corn, waxy corn, rice and waxy rice. These starches have the added benefits of good clarity and short, smooth texture.
An object of the present invention is to provide a stabilized, particularly a stabilized, crosslinked waxy potato starch.
Another object of the present invention is to provide such a starch with a high viscosity, good clarity, and a short, smooth texture.
A further object of the present invention is to provide a composition, particularly a foodstuff, which uses less starch to obtain its desired viscosity.
These and other objects of the present invention will become apparent to one skilled in the art from the following detailed description and examples below.